Process for the preparation of a tetraalkylcyclobutane-1,3-diol using an iridium-promoted cobalt-based catalyst

ABSTRACT

The present disclosure relates to the production of a 2,2,4,4-tetraalkylcyclobutane-1,3-diol. In one embodiment, the present invention relates to the production of a 2,2,4,4-tetraalkylcyclobutane-1,3-diol by hydrogenation of a 2,2,4,4-tetraalkylcyclobutane-1,3-dione in the presence of an iridium-promoted cobalt-based catalyst.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application Ser. No. 60/872,394 filed on Dec. 2, 2006, whichis hereby incorporated by reference.

FIELD OF THE INVENTION

The present disclosure relates to the production of a2,2,4,4-tetraalkylcyclobutane-1,3-diol. In one embodiment, the presentinvention relates to the production of a2,2,4,4-tetraalkylcyclobutane-1,3-diol by hydrogenation of a2,2,4,4-tetraalkylcyclobutane-1,3-dione in the presence of aniridium-promoted cobalt-based catalyst.

BACKGROUND OF THE INVENTION

2,2,4,4-Tetramethylcyclobutane-1,3-diol is an important intermediate forproducing a variety of polymeric materials having advantageousproperties. For example, polyesters derived from dicarboxylic acids and2,2,4,4-tetramethylcyclobutane-1,3-diol can possess higher glasstransition temperatures, superior weatherability, and/or improvedhydrolytic stability compared to polyesters prepared from othercommonly-used, polyester forming diols. A2,2,4,4-tetramethylcyclobutane-1,3-diol of Formula I is typicallyproduced by the catalytic hydrogenation of the corresponding2,2,4,4-tetramethylcyclobutane-1,3-dione as shown below.

Typically, the hydrogenation of 2,2,4,4-tetramethylcyclobutane-1,3-dioneproduces the corresponding 2,2,4,4-tetramethylcyclobutane-1,3-diol as amixture of cis and trans isomers. It would be desirable to produce2,2,4,4-tetramethylcyclobutane-1,3-diol with a specific cis/trans isomerratio in order to control glass transition temperatures and/orcrystallization rates in copolyesters.

SUMMARY OF THE INVENTION

The present disclosure relates to the production of a2,2,4,4-tetraalkylcyclobutane-1,3-diol. In one embodiment, the presentinvention relates to the production of a2,2,4,4-tetraalkylcyclobutane-1,3-diol by hydrogenation of a2,2,4,4-tetraalkylcyclobutane-1,3-dione in the presence of aniridium-promoted cobalt-based catalyst.

In one embodiment, the present invention relates to processes forproducing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol, comprisingcontacting a 2,2,4,4-tetraalkylcyclobutane-1,3-dione with hydrogen inthe presence of an iridium-promoted cobalt-based catalyst underconditions of temperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol, wherein the alkyl radicals eachindependently have 1 to 8 carbon atoms.

In one embodiment, the present invention relates to processes forproducing 2,2,4,4-tetramethylcyclobutane-1,3-diol, comprising contacting2,2,4,4-tetramethylcyclobutane-1,3-dione, an iridium-promotedcobalt-based catalyst, a non-protic solvent, and hydrogen in ahydrogenation zone under conditions of temperature and pressuresufficient to form 2,2,4,4-tetramethylcyclobutane-1,3-diol.

In one embodiment, the present invention relates to processescomprising: (1) feeding isobutyric anhydride to a pyrolysis zone,wherein the isobutyric anhydride is heated at a temperature of 350° C.to 600° C. to produce a vapor effluent comprising dimethylketene,isobutyric acid, and unreacted isobutyric anhydride; (2) cooling thevapor effluent to condense isobutyric acid and isobutyric anhydride andseparating the condensate from the dimethylketene vapor; (3) feeding thedimethylketene vapor to an absorption zone, wherein the dimethylketenevapor is contacted with and dissolved in a solvent comprising an estercontaining 4 to 20 carbon atoms and consisting of residues of analiphatic carboxylic acid and an alkanol to produce an absorption zoneeffluent comprising a solution of dimethylketene in the solvent; (4)feeding the absorption zone effluent to a dimerization zone wherein theabsorption zone effluent is heated at a temperature ranging from 70° C.to 140° C. to convert dimethylketene to2,2,4,4-tetramethylcyclobutane-1,3-dione to produce a dimerization zoneeffluent comprising a solution of2,2,4,4-tetramethylcyclobutane-1,3-dione in the solvent; and (5)contacting the 2,2,4,4-tetramethylcyclobutane-1,3-dione with hydrogen inthe presence of an iridium-promoted cobalt-based catalyst underconditions of temperature and pressure sufficient to form a2,2,4,4-tetramethylcyclobutane-1,3-diol.

Additional objects and advantages of the invention will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention will be realized and attained bymeans of the elements and combinations particularly pointed out in theappended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention, as claimed.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure may be understood more readily by reference tothe following detailed description of certain embodiments of theinvention and the working examples.

In accordance with the purpose of this invention, certain embodiments ofthe invention are described in the Summary of the Invention and arefurther described herein below. Also, other embodiments of the inventionare described herein.

The term “iridium-promoted cobalt-based catalyst” refers to acobalt-based catalyst that has been promoted by iridium. Thecobalt-based catalyst is promoted by contacting the catalyst with asolution of iridium under appropriate conditions. Appropriate promotingconditions are exemplified, but not limited to, the methods in theexamples below. Other conventional methods of applying promoters tocatalysts are well-known to those of skill in the art. Applicants makeno representation regarding the nature of the interaction of the iridiumcompound and the cobalt-based catalyst, but instead contemplate aswithin the scope of the present invention all iridium-promotedcobalt-based catalysts that are active in the claimed processes. In oneembodiment, the yield of the hydrogenation reaction is greater than 10%,for example, greater than 40%, for example, greater than 50%, forexample, greater than 60%, for example, greater than 70%, for example,greater than 80%, for example, greater than 90%.

The term cobalt-based catalyst refers to a catalyst comprising cobaltincluding, for example and without limitation, zero valent cobalt,cobalt in an ionic form, and cobalt in an alloy.

The term “iridium” includes, for example and without limitation, zerovalent iridium, iridium in ionic form, and iridium in an alloy.

Unless otherwise indicated, all numbers expressing quantities ofingredients, properties such as molecular weight, reaction conditions,and so forth used in the specification and claims are to be understoodas being modified in all instances by the term “about.” Accordingly,unless indicated to the contrary, the numerical parameters set forth inthe following specification and attached claims are approximations thatmay vary depending upon the desired properties sought to be obtained bythe present invention. At the very least, each numerical parametershould at least be construed in light of the number of reportedsignificant digits and by applying ordinary rounding techniques.Further, the ranges stated in this disclosure and the claims areintended to include the entire range specifically and not just theendpoint(s). For example, a range stated to be 0 to 10 is intended todisclose all whole numbers between 0 and 10 such as, for example, 1, 2,3, 4, etc., as well as the endpoints 0 and 10. Also, a range associatedwith chemical substituent groups such as, for example, “C₁ to C₅hydrocarbons,” is intended to specifically include and disclose C₁ andC₅ hydrocarbons as well as C₂, C₃, and C₄ hydrocarbons.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements.

As used in the specification and the appended claims, the singular forms“a,” “an,” and “the” include their plural referents unless the contextclearly dictates otherwise. For example, reference to the processing ormaking of a “catalyst,” or a “promoter,” is intended to include theprocessing or making of a plurality of catalysts, or promoters.References to a composition containing or including “a” promoter or “a”catalyst is intended to include other promoters or other catalysts,respectively, in addition to the one named.

By “comprising” or “containing” or “including” we mean that at least thenamed compound, element, particle, or method step, etc., is present inthe composition or article or method, but we do not exclude the presenceof other compounds, catalysts, materials, particles, method steps, etc.,even if the other such compounds, materials, particles, method steps,etc., have the same function as what is named, unless expressly excludedin the claims.

It is also to be understood that the mention of one or more method stepsdoes not preclude the presence of additional method steps before orafter the combined recited steps or intervening method steps betweenthose steps expressly identified. Moreover, the lettering of processsteps or ingredients is a convenient means for identifying discreteactivities or ingredients and it is to be understood that the recitedlettering can be arranged in any sequence, unless otherwise indicated.

In one embodiment, the present invention provides processes for making a2,2,4,4-tetraalkylcyclobutane-1,3-diol by hydrogenation of a2,2,4,4-tetraalkylcyclobutane-1,3-dione. In a general embodiment, theinvention provides processes for making a2,2,4,4-tetraalkylcyclobutane-1,3-diol comprising contacting a2,2,4,4-tetraalkylcyclobutane-1,3-dione with hydrogen in the presence ofan iridium-promoted cobalt-based catalyst. In one embodiment, thepresent invention is useful for the preparation of2,2,4,4-tetramethylcyclobutane-1,3-diol from2,2,4,4-tetramethylcyclobutane-1,3-dione.

The hydrogenation reaction of 2,2,4,4-tetraalkylcyclobutane-1,3-dione toproduce a 2,2,4,4-tetraalkylcyclobutane-1,3-diol of Formula II is shownbelow:

wherein R₁, R₂, R₃, and R₄ each independently represent an alkylradical, for example, a lower alkyl radical having 1 to 8 carbon atoms.The alkyl radicals may be linear, branched, or a combination of linearand branched alkyl radicals. The2,2,4,4-tetraalkylcyclobutane-1,3-dione, for example,2,2,4,4-tetramethylcyclobutane-1,3-dione, is hydrogenated to thecorresponding 2,2,4,4-tetraalkylcyclobutane-1,3-diol, for example,2,2,4,4-tetramethylcyclobutane-1,3-diol, in accordance with the presentprocesses.

In one embodiment, the alkyl radicals R₁, R₂, R₃, and R₄ on the2,2,4,4-tetraalkylcyclobutane-1,3-dione each independently have 1 to 8carbon atoms. Other 2,2,4,4-tetraalkylcyclobutane-1,3-diones that aresuitably reduced to the corresponding diols include, but are not limitedto, 2,2,4,4-tetraethylcyclobutane-1,3-dione,2,2,4,4-tetra-n-propylcyclobutane-1,3-dione,2,2,4,4-tetra-n-butylcyclobutane-1,3-dione,2,2,4,4-tetra-n-pentylcyclobutane-1,3-dione,2,2,4,4-tetra-n-hexylcyclobutane-1,3-dione,2,2,4,4-tetra-n-heptylcyclobutane-1,3-dione,2,2,4,4-tetra-n-octylcyclobutane-1,3-dione,2,2-dimethyl-4,4-diethylcyclobutane-1,3-dione,2-ethyl-2,4,4-trimethylcyclobutane-1,3-dione,2,4-dimethyl-2,4-diethyl-cyclobutane-1,3-dione,2,4-dimethyl-2,4-di-n-propylcyclobutane-1,3-dione,2,4-n-dibutyl-2,4-diethylcyclobutane-1,3-dione,2,4-dimethyl-2,4-diisobutylcyclobutane-1,3-dione, and2,4-diethyl-2,4-diisoamylcyclobutane-1,3-dione.

In other embodiments, the alkyl radicals R₁, R₂, R₃, and R₄ on the2,2,4,4-tetraalkylcyclobutane-1,3-dione each independently have 1 to 6carbon atoms, or 1 to 5 carbon atoms, or 1 to 4 carbon atoms, or 1 to 3carbon atoms, or 1 to 2 carbon atoms. In another embodiment, the alkylradicals R₁, R₂, R₃, and R₄ on the2,2,4,4-tetraalkylcyclobutane-1,3-dione each have 1 carbon atom.

In one embodiment, the cobalt-based catalyst is promoted with iridium.The amount of the iridium compound that may be incorporated by thecobalt-based catalyst depends upon the promoting conditions but, forexample, may range from 0.01 to 10 weight percent (abbreviated herein as“wt %) based upon the total weight of the promoted cobalt-basedcatalyst. For example, in some embodiments, the processes of the presentinvention may use a cobalt-based catalyst promoted with iridiumcomprising 0.01 to 10 weight percent (wt %) iridium, based on the totalweight of the promoted cobalt-based catalyst. Other examples of iridiumpromoting levels on the promoted cobalt-based catalyst are 0.05 to 7 wt% iridium and 1 to 5 wt % iridium. The cobalt ranges from 1 to 70 wt %,or 5 to 65 wt %, or 10 to 60 wt %, based on the total weight of thecatalyst.

The iridium compounds used as promoter compounds include, but are notlimited to, water soluble iridium compounds. Such iridium compoundsinclude, but are not limited to, their oxides, hydroxides, andalkoxides, and the corresponding salts such as acetates, carbonates,phosphates, and nitrates.

Suitable supports for the iridium-promoted cobalt-based catalystsinclude, but are not limited to, silica, alumina, aluminosilicate,silica/alumina, kieselguhr, titania, graphite, silicon carbide, carbon,zirconia, chromate, barium chromate, zinc oxide, clay, and alumina-clay.Suitable forms of the support include powder, extrudate, spheres, orpellets.

The processes typically are conducted at temperatures in the range of75° C. to 250° C. The processes typically are conducted at pressures inthe range of 689 kPa (100 psi) (7 bar) to 41,368 kPa (6000 psi) (420bar). Further examples of temperatures and/or pressures at which theprocesses of the invention may be operated are 120° C. to 200° C. at1380 kPa (200 psi) (14 bar) to 20,684 kPa (3000 psi) (207 bar), and 130°C. to 180° C. at 2068 kPa (300 psi) (21 bar) to 14,789 kPa (2000 psi)(140 bar). For certain embodiments of the present invention, thehydrogenation process has a temperature ranging from 130° C. to 140° C.and a pressure ranging from 3450 kPa (500 psi) (34.5 barg) to 10000 kPa(1450 psi) (100 barg). For certain embodiments of the present invention,the hydrogenation process has a temperature ranging from 160° C. to 170°C. and a pressure ranging from 3450 kPa (500 psi) (34.5 barg) to 10000kPa (1450 psi) (100 barg).

For certain embodiments of the present invention, the hydrogenationprocess has a temperature range chosen from 75° C. to 250 C, 80° C. to250° C., 90° C. to 250° C., 100 C to 250° C., 110° C. to 250° C., 120°C. to 250 C, 130° C. to 250° C., 140° C. to 250° C., 150° C. to 250° C.,160 C to 250° C., 170 C to 250° C., 180 C to 250 C, 190° C. to 250° C.,200° C. to 250° C., 210° C. to 250 C, 220° C. to 250° C., 230° C. to250° C., or 240° C. to 250° C. For certain embodiments of the presentinvention, the hydrogenation process has a temperature range chosen from75° C. to 240° C., 80° C. to 240° C., 90° C. to 240° C., 100° C. to 240°C., 110 C to 240° C., 120° C. to 240° C., 130° C. to 240° C., 140° C. to240° C., 150° C. to 240° C., 160° C. to 240° C., 170° C. to 240° C.,180° C. to 240° C., 190° C. to 240° C., 200° C. to 240° C., 210° C. to240 C, 220° C. to 240° C., or 230° C. to 240° C. For certain embodimentsof the present invention, the hydrogenation process has a temperaturerange chosen from 75° C. to 230° C., 80° C. to 230° C., 90° C. to 230°C., 100° C. to 230° C., 110° C. to 230° C., 120° C. to 230° C., 130° C.to 230° C., 140° C. to 230° C., 150° C. to 230° C., 160° C. to 230 C,170° C. to 230° C., 180 C to 230° C., 190° C. to 230° C., 200° C. to230° C., 210° C. to 230° C., or 220° C. to 230° C.

For certain embodiments of the present invention, the hydrogenationprocess has a temperature range chosen from 75° C. to 220° C., 80° C. to220° C., 90° C. to 220° C., 100° C. to 220° C., 110° C. to 220° C., 120°C. to 220° C., 130° C. to 220° C., 140° C. to 220° C., 150° C. to 220°C., 160° C. to 220° C., 170° C. to 220° C., 180° C. to 220° C., 190° C.to 220° C., 200° C. to 220° C., or 210° C. to 220° C. For certainembodiments of the present invention, the hydrogenation process has atemperature range chosen from 75° C. to 210° C., 80° C. to 210° C., 90°C. to 210° C., 100° C. to 210° C., 110° C. to 210° C., 120° C. to 210°C., 130° C. to 210° C., 140° C. to 210° C., 150° C. to 210° C., 160° C.to 210° C., 170° C. to 210° C., 180° C. to 210° C., 190° C. to 210° C.,or 200° C. to 210° C. For certain embodiments of the present invention,the hydrogenation process has a temperature range chosen from 75° C. to200° C., 80° C. to 200° C., 90° C. to 200° C., 100° C. to 200° C., 110°C. to 200° C., 120° C. to 200° C., 130° C. to 200° C., 140° C. to 200°C., 150° C. to 200° C., 160° C. to 200° C., 170° C. to 200° C., 180° C.to 200° C., or 190° C. to 200° C.

For certain embodiments of the present invention, the hydrogenationprocess has a temperature range chosen from 75° C. to 190° C., 80° C. to190° C., 90° C. to 190° C., 100° C. to 190° C., 110° C. to 190° C., 120°C. to 190° C., 130° C. to 190° C., 140° C. to 190° C., 150° C. to 190°C., 160° C. to 190° C., 170° C. to 190° C., or 180° C. to 190° C. Forcertain embodiments of the present invention, the hydrogenation processhas a temperature range chosen from 75° C. to 180° C., 80° C. to 180°C., 90° C. to 180° C., 100° C. to 180° C., 110° C. to 180° C., 120° C.to 180° C., 130° C. to 180° C., 140° C. to 180° C., 150° C. to 180° C.,160° C. to 180° C., or 170° C. to 180° C. For certain embodiments of thepresent invention, the hydrogenation process has a temperature rangechosen from 75° C. to 170° C., 80° C. to 170° C., 90° C. to 170° C.,100° C. to 170° C., 110° C. to 170° C., 120° C. to 170° C., 130° C. to170° C., 140° C. to 170° C., 150° C. to 170° C., or 160° C. to 170° C.

For certain embodiments of the present invention, the hydrogenationprocess has a temperature range chosen from 75° C. to 160° C., 80° C. to160° C., 90° C. to 160° C., 100° C. to 160° C., 110° C. to 160° C., 120°C. to 160° C., 130° C. to 160° C., 140° C. to 160° C., or 150° C. to160° C. For certain embodiments of the present invention, thehydrogenation process has a temperature range chosen from 75° C. to 150°C., 80° C. to 150° C., 90° C., to 150° C., 100° C. to 150° C., 110° C.to 150° C., 120° C. to 150° C., 130° C. to 150° C., or 140° C. to 150°C. For certain embodiments of the present invention, the hydrogenationprocess has a temperature range chosen from 75° C. to 140° C., 80° C. to140° C., 90° C. to 140° C., 100° C. to 140° C., 110° C. to 140° C., 120°C. to 140° C., or 130° C. to 140° C. For certain embodiments of thepresent invention, the hydrogenation process has a temperature rangechosen from 75° C. to 130° C., 80° C. to 130° C., 90° C. to 130° C.,100° C. to 130° C., 110° C. to 130° C., or 120° C. to 130° C.

For certain embodiments of the present invention, the hydrogenationprocess has a temperature range chosen from 75° C. to 120° C., 80° C. to120° C., 90° C. to 120° C., 100° C. to 120° C., or 110° C. to 120° C.For certain embodiments of the present invention, the hydrogenationprocess has a temperature range chosen from 75° C. to 110° C., 80° C. to110° C., 90° C. to 110° C., or 100° C. to 110° C. For certainembodiments of the present invention, the hydrogenation process has atemperature range chosen from 75° C. to 100° C., 80° C. to 100° C., or90° C. to 100° C. For certain embodiments of the present invention, thehydrogenation process has a temperature range chosen from 75° C. to 90°C., or 80° C. to 90° C. For certain embodiments of the presentinvention, the hydrogenation process has a temperature range chosen from75° C. to 80° C.

For certain embodiments of the present invention, the hydrogenationprocess has a pressure range chosen from 100 psi to 6000 psi, 200 psi to6000 psi, 300 psi to 6000 psi, 400 psi to 6000 psi, 500 psi to 6000 psi,1000 psi to 6000 psi, 1500 psi to 6000 psi, 2000 psi to 6000 psi, 2500psi to 6000 psi, 3000 psi to 6000 psi, 3500 psi to 6000 psi, 4000 psi to6000 psi, 4500 psi to 6000 psi, 5000 psi to 6000 psi, or 5500 psi to6000 psi. For certain embodiments of the present invention, thehydrogenation process has a pressure range chosen from 100 psi to 5500psi, 200 psi to 5500 psi, 300 psi to 5500 psi, 400 psi to 5500 psi, 500psi to 5500 psi, 1000 psi to 5500 psi, 1500 psi to 5500 psi, 2000 psi to5500 psi, 2500 psi to 5500 psi, 3000 psi to 5500 psi, 3500 psi to 5500psi, 4000 psi to 5500 psi, 4500 psi to 5500 psi, or 5000 psi to 5500psi.

For certain embodiments of the present invention, the hydrogenationprocess has a pressure range chosen from 100 psi to 5000 psi, 200 psi to5000 psi, 300 psi to 5000 psi, 400 psi to 5000 psi, 500 psi to 5000 psi,1000 psi to 5000 psi, 1500 psi to 5000 psi, 2000 psi to 5000 psi, 2500psi to 5000 psi, 3000 psi to 5000 psi, 3500 psi to 5000 psi, 4000 psi to5000 psi, or 4500 psi to 5000 psi. For certain embodiments of thepresent invention, the hydrogenation process has a pressure range chosenfrom 100 psi to 4500 psi, 200 psi to 4500 psi, 300 psi to 4500 psi, 400psi to 4500 psi, 500 psi to 4500 psi, 1000 psi to 4500 psi, 1500 psi to4500 psi, 2000 psi to 4500 psi, 2500 psi to 4500 psi, 3000 psi to 4500psi, 3500 psi to 4500 psi, or 4000 psi to 4500 psi. For certainembodiments of the present invention, the hydrogenation process has apressure range chosen from 100 psi to 4000 psi, 200 psi to 4000 psi, 300psi to 4000 psi, 400 psi to 4000 psi, 500 psi to 4000 psi, 1000 psi to4000 psi, 1500 psi to 4000 psi, 2000 psi to 4000 psi, 2500 psi to 4000psi, 3000 psi to 4000 psi, or 3500 psi to 4000 psi.

For certain embodiments of the present invention, the hydrogenationprocess has a pressure range chosen from 100 psi to 3500 psi, 200 psi to3500 psi, 300 psi to 3500 psi, 400 psi to 3500 psi, 500 psi to 3500 psi,1000 psi to 3500 psi, 1500 psi to 3500 psi, 2000 psi to 3500 psi, 2500psi to 3500 psi, or 3000 psi to 3500 psi. For certain embodiments of thepresent invention, the hydrogenation process has a pressure range chosenfrom 100 psi to 3000 psi, 200 psi to 3000 psi, 300 psi to 3000 psi, 400psi to 3000 psi, 500 psi to 3000 psi, 1000 psi to 3000 psi, 1500 psi to3000 psi, 2000 psi to 3000 psi, or 2500 psi to 3000 psi. For certainembodiments of the present invention, the hydrogenation process has apressure range chosen from 100 psi to 2500 psi, 200 psi to 2500 psi, 300psi to 2500 psi, 400 psi to 2500 psi, 500 psi to 2500 psi, 1000 psi to2500 psi, 1500 psi to 2500 psi, 2000 psi to 2500 psi.

For certain embodiments of the present invention, the hydrogenationprocess has a pressure range chosen from 100 psi to 2000 psi, 200 psi to2000 psi, 300 psi to 2000 psi, 400 psi to 2000 psi, 500 psi to 2000 psi,1000 psi to 2000 psi, or 1500 psi to 2000 psi. For certain embodimentsof the present invention, the hydrogenation process has a pressure rangechosen from 100 psi to 1500 200 psi to 1500 psi, 300 psi to 1500 psi,400 psi to 1500 psi, 500 psi to 1500 psi, or 1000 psi to 1500 psi. Forcertain embodiments of the present invention, the hydrogenation processhas a pressure range chosen from 100 psi to 1000 psi, 200 psi to 1000psi, 300 psi to 1000 psi, 400 psi to 1000 psi, or 500 psi to 1000 psi.

For certain embodiments of the present invention, the hydrogenationprocess has a pressure range chosen from 100 psi to 500 psi, 200 psi to500 psi, 300 psi to 500 psi, or 400 psi to 500 psi. For certainembodiments of the present invention, the hydrogenation process has apressure range chosen from 100 psi to 400 psi, 200 psi to 400 psi, or300 psi to 400 psi. For certain embodiments of the present invention,the hydrogenation process has a pressure range chosen from 100 psi to300 psi, or 200 psi to 300 psi. For certain embodiments of the presentinvention, the hydrogenation process has a pressure range chosen from100 psi to 200 psi.

It is contemplated that the processes of the invention can be carriedout at least one of the temperature ranges disclosed herein and at leastone of the pressure ranges disclosed herein.

The source and purity of the hydrogen gas used in the processes of thepresent invention are not critical. The hydrogen gas used in theprocesses may comprise fresh hydrogen or a mixture of fresh hydrogen andrecycled hydrogen. The hydrogen gas can be a mixture of hydrogen and,optionally, minor amounts, typically less than 30 mole %, of componentssuch as CO and CO₂, and inert gases, such as argon, nitrogen, ormethane. Typically, the hydrogen gas comprises at least 70 mole % ofhydrogen. For example, the hydrogen gas comprises at least 90 mole % or,in another example, at least 97 mole %, of hydrogen. The hydrogen gasmay be obtained from any of the conventional sources well known in theart such as, for example, by partial oxidation or steam reforming ofnatural gas. Pressure swing absorption can be used if a high purityhydrogen gas is desired. If hydrogen gas recycle is utilized in one ofthe processes, then the recycle hydrogen gas may contain minor amountsof one or more products of the hydrogenation reaction which have notbeen fully condensed in the product recovery stage downstream from thehydrogenation zone.

The hydrogenation of 2,2,4,4-tetraalkylcyclobutane-1,3-dione typicallyproduces cis-2,2,4,4-tetraalkylcyclobutane-1,3-diol andtrans-2,2,4,4-tetraalkylcyclobutane-1,3-diol. In certain embodiments ofthe present invention, the cis/trans molar ratio ranges from 1.7 to 0.0or 1.6 to 0.0 or 1.5 to 0.0 or 1.4 to 0.0 or 1.3 to 0.0 or 1.2 to 0.0 or1.1 to 0.0 or 1.0 to 0.0 or 0.9 to 0.0 or 0.8 to 0.0 or 0.7 to 0.0 or0.6 to 0.0 or 0.5 to 0.0 or 0.4 to 0.0 or 0.3 to 0.0 or 0.2 to 0.0 or0.1 to 0.0. In certain embodiments of the present invention, thecis/trans molar ratio ranges from 1.7 to 0.1 or 1.6 to 0.1 or 1.5 to 0.1or 1.4 to 0.1 or 1.3 to 0.1 or 1.2 to 0.1 or 1.1 to 0.1 or 1.0 to 0.1 or0.9 to 0.1 or 0.8 to 0.1 or 0.7 to 0.1 or 0.6 to 0.1 or 0.5 to 0.1 or0.4 to 0.1 or 0.3 to 0.1 or 0.2 to 0.1. In certain embodiments of thepresent invention, the cis/trans molar ratio ranges from 1.7 to 0.2 or1.6 to 0.2 or 1.5 to 0.2 or 1.4 to 0.2 or 1.3 to 0.2 or 1.2 to 0.2 or1.1 to 0.2 or 1.0 to 0.2 or 0.9 to 0.2 or 0.8 to 0.2 or 0.7 to 0.2 or0.6 to 0.2 or 0.5 to 0.2 or 0.4 to 0.2 or 0.3 to 0.2.

In certain embodiments of the present invention, the cis/trans molarratio ranges from 1.7 to 0.3 or 1.6 to 0.3 or 1.5 to 0.3 or 1.4 to 0.3or 1.3 to 0.3 or 1.2 to 0.3 or 1.1 to 0.3 or 1.0 to 0.3 or 0.9 to 0.3 or0.8 to 0.3 or 0.7 to 0.3 or 0.6 to 0.3 or 0.5 to 0.3 or 0.4 to 0.3. Incertain embodiments of the present invention, the cis/trans molar ratioranges from 1.7 to 0.4 or 1.6 to 0.4 or 1.5 to 0.4 or 1.4 to 0.4 or 1.3to 0.4 or 1.2 to 0.4 or 1.1 to 0.4 or 1.0 to 0.4 or 0.9 to 0.4 or 0.8 to0.4 or 0.7 to 0.4 or 0.6 to 0.4 or 0.5 to 0.4. In certain embodiments ofthe present invention, the cis/trans molar ratio ranges from 1.7 to 0.5or 1.6 to 0.5 or 1.5 to 0.5 or 1.4 to 0.5 or 1.3 to 0.5 or 1.2 to 0.5 or1.1 to 0.5 or 1.0 to 0.5 or 0.9 to 0.5 or 0.8 to 0.5 or 0.7 to 0.5 or0.6 to 0.5. In certain embodiments of the present invention, thecis/trans molar ratio ranges from 1.7 to 0.6 or 1.6 to 0.6 or 1.5 to 0.6or 1.4 to 0.6 or 1.3 to 0.6 or 1.2 to 0.6 or 1.1 to 0.6 or 1.0 to 0.6 or0.9 to 0.6 or 0.8 to 0.6 or 0.7 to 0.6. In certain embodiments of thepresent invention, the cis/trans molar ratio ranges from 1.7 to 0.7 or1.6 to 0.7 or 1.5 to 0.7 or 1.4 to 0.7 or 1.3 to 0.7 or 1.2 to 0.7 or1.1 to 0.7 or 1.0 to 0.7 or 0.9 to 0.7 or 0.8 to 0.7. In certainembodiments of the present invention, the cis/trans molar ratio rangesfrom 1.7 to 0.8 or 1.6 to 0.8 or 1.5 to 0.8 or 1.4 to 0.8 or 1.3 to 0.8or 1.2 to 0.8 or 1.1 to 0.8 or 1.0 to 0.8 or 0.9 to 0.8.

In certain embodiments of the present invention, the cis/trans molarratio ranges from 1.7 to 0.9 or 1.6 to 0.9 or 1.5 to 0.9 or 1.4 to 0.9or 1.3 to 0.9 or 1.2 to 0.9 or 1.1 to 0.9 or 1.0 to 0.9. In certainembodiments of the present invention, the cis/trans molar ratio rangesfrom 1.7 to 1.0 or 1.6 to 1.0 or 1.5 to 1.0 or 1.4 to 1.0 or 1.3 to 1.0or 1.2 to 1.0 or 1.1 to 1.0. In certain embodiments of the presentinvention, the cis/trans molar ratio ranges from 1.7 to 1.1 or 1.6 to1.1 or 1.5 to 1.1 or 1.4 to 1.1 or 1.3 to 1.1 or 1.2 to 1.1. In certainembodiments of the present invention, the cis/trans molar ratio rangesfrom 1.7 to 1.2 or 1.6 to 1.2 or 1.5 to 1.2 or 1.4 to 1.2 or 1.3 to 1.2.In certain embodiments of the present invention, the cis/trans molarratio ranges from 1.7 to 1.3 or 1.6 to 1.3 or 1.5 to 1.3 or 1.4 to 1.3.In certain embodiments of the present invention, the cis/trans molarratio ranges from 1.7 to 1.4 or 1.6 to 1.4 or 1.5 to 1.4. In certainembodiments of the present invention, the cis/trans molar ratio rangesfrom 1.7 to 1.5 or 1.6 to 1.5. In one embodiment of the presentinvention, the cis/trans molar ratio ranges from 1.7 to 1.6.

The processes of this invention may be carried out in the absence orpresence of a solvent, e.g., a solvent for the2,2,4,4-tetraalkylcyclobutane-1,3-dione being hydrogenated which iscompatible with the catalyst and the hydrogenation product or products.Examples of such solvents include alcohols such as methanol and ethanol;ethers, such as dimethyl ether and diethyl ether; glycols such as mono-,di- and tri-ethylene glycol; glycol ethers, such as ethylene glycolmonobutyl ether and diethylene glycol monobutyl ether; saturatedhydrocarbons such as hexane, cyclohexane, octane, and decane; andesters, such as isopropyl isobutyrate, isobutyl propionate, octylacetate, isobutyl isobutyrate, isobutyl acetate, and the like. In oneembodiment, the solvent is isobutyl isobutyrate. In one embodiment, the2,2,4,4-tetraalkylcyclobutane-1,3-dione is dissolved in the solvent at aconcentration of 1 to 60% (w/w), for example 5 to 50%, or 10 to 25%. Inone embodiment in which the solvent is isobutyl isobutyrate, the2,2,4,4-tetraalkylcyclobutane-1,3-dione is dissolved in the solvent at aconcentration of 1 to 60% (w/w), for example 5 to 50%, or 10 to 25%. Incertain embodiments, the process is conducted in the absence of solventand use the neat, molten 2,2,4,4-tetraalkylcyclobutane-1,3-dione aloneor as a mixture with the 2,2,4,4-tetraalkylcyclobutane-1,3-diol andother hydrogenation products, including1-hydroxy-2,2,4-trimethyl-3-pentanone,3-hydroxy-2,2,4,4,-tetramethylcyclobutane-1-one, and2,2,4-trimethyl-1,3-pentanediol, as the feed to the process.

Another embodiment of the present invention is drawn to processes toproduce a 2,2,4,4-tetraalkylcyclobutane-1,3-diol comprising (1) feedingisobutyric anhydride to a pyrolysis zone to produce a vapor effluentcomprising dimethylketene, isobutyric acid, and unreacted isobutyricanhydride; (2) cooling the vapor effluent to condense isobutyric acidand isobutyric anhydride and separating the condensate from thedimethylketene vapor; (3) feeding the dimethylketene vapor to anabsorption zone wherein the dimethylketene vapor is dissolved in asolvent comprising an ester containing 4 to 20 carbon atoms andconsisting of residues of an aliphatic carboxylic acid and an alkanol toproduce an absorption zone effluent comprising a solution ofdimethylketene in the solvent; (4) feeding the absorption zone effluentto a dimerization zone wherein the absorption effluent is heated toconvert dimethylketene to 2,2,4,4-tetramethylcyclobutane-1,3-dione toproduce a dimerization zone effluent comprising a solution of2,2,4,4-tetramethylcyclobutane-1,3-dione in the solvent; and (5)contacting the 2,2,4,4-tetraalkylcyclobutane-1,3-dione with hydrogen inthe presence of an iridium-promoted cobalt-based catalyst underconditions of temperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol.

Another embodiment of the present invention is drawn to processes toproduce a 2,2,4,4-tetraalkylcyclobutane-1,3-diol comprising (1) feedinga dialkyl carboxylic acid to a pyrolysis zone wherein the dialkylcarboxylic acid produces a vapor effluent comprising dialkylketene,water, and unreacted dialkyl carboxylic acid; (2) cooling the vaporeffluent to condense water and dialkyl carboxylic acid and separatingthe condensate from the dialkylketene vapor; (3) feeding thedialkylketene vapor to an absorption zone wherein the dialkylketenevapor is dissolved in a solvent comprising an ester containing 4 to 20carbon atoms and consisting of residues of an aliphatic carboxylic acidand an alkanol to produce an absorption zone effluent comprising asolution of dialkylketene in the solvent; (4) feeding the absorptionzone effluent to a dimerization zone wherein the absorption zoneeffluent is heated to convert dialkylketene to2,2,4,4-tetraalkylcyclobutane-1,3-dione to produce a dimerization zoneeffluent comprising a solution of2,2,4,4-tetraalkylcyclobutane-1,3-dione in the solvent; and (5)contacting the tetraalkylcyclobutane-1,3-dione with hydrogen in thepresence of an iridium-promoted cobalt-based catalyst under conditionsof temperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol.

The nature of the process for making the dialkylketene is not criticaland any conventional method may be used, including, but not limited to,the methods disclosed in U.S. Pat. Nos. 1,602,699, 2,160,841, 2,202,046,2,278,537, 2,806,064, 3,201,474, 3,259,469, 3,366,689, 3,403,181,5,475,144 and 6,232,504, all of which are incorporated herein byreference for their disclosure of processes for making a dialkylketene.Processes for the preparation of ketenes, for example, dimethylketene,and cyclobutane-1,3-diones, for example,2,2,4,4-tetramethylcyclobutane-1,3-dione, may be combined with allaspects of the present invention related to preparation of the2,2,4,4-tetraalkylcyclobutane-1,3-diols, including mixtures of cis andtrans-2,2,4,4-tetraalkylcyclobutane-1,3-diols.

All of these novel processes may be carried out as a batch,semi-continuous, or continuous process and may utilize a variety ofreactor types. Examples of suitable reactor types include, but are notlimited to, stirred tank, continuous stirred tank, slurry, tubular,fixed bed, and trickle bed. The term “continuous” as used herein means aprocess wherein reactants are introduced and products withdrawnsimultaneously in an uninterrupted manner. By “continuous” it is meantthat the process is substantially or completely continuous in operation,in contrast to a “batch” process. “Continuous” is not meant in any wayto prohibit normal interruptions in the continuity of the process dueto, for example, start-up, reactor maintenance, or scheduled shut downperiods. The term “batch” process as used herein means a process whereinall the reactants are added to the reactor and then processed accordingto a predetermined course of reaction during which essentially nomaterial is fed into or removed from the reactor. For example, in abatch operation, a slurry of the catalyst in the cyclobutanedione and/ora solvent in which the cyclobutanedione has been dissolved is fed to apressure vessel equipped with means for agitation. The pressure vesselis then pressurized with hydrogen to a predetermined pressure followedby heating to bring the reaction mixture to the desired temperature.After the hydrogenation is complete, the reaction mixture is removedfrom the pressure vessel, the catalyst is separated by filtration, andthe 2,2,4,4-tetramethylcyclobutane-1,3-diol product is isolated, forexample, in a distillation train or by crystallization. The term“semicontinuous” means a process where some of the reactants are chargedat the beginning of the process and the remaining reactants are fedcontinuously as the reaction progresses. Alternatively, a semicontinuousprocess may also include a process similar to a batch process in whichall the reactants are added at the beginning of the process except thatone or more of the products are removed continuously as the reactionprogresses.

The process may be operated as a continuous process, althoughsemi-continuous and batch processes are sill within the scope of theinvention. Continuous operation may utilize a fixed bed with a largerparticle size of catalyst such as, for example, granules, pellets,various multilobal shaped pellets, rings, or saddles that are well knownto skilled persons in the art. As an example of a continuous process,the catalyst bed may be fixed in a high pressure, tubular or columnarreactor and the liquid cyclobutanedione, dissolved in a solvent ifnecessary or desired, fed continuously into the top of the bed atelevated pressure and temperature, and the crude hydrogenation productremoved from the base of the reactor. Alternatively, it is possible tofeed the cyclobutanedione into the bottom of the bed and remove thecrude product from the top of the reactor. It is also possible to usetwo or more catalyst beds or hydrogenation zones connected in parallelor in series to improve conversion, to reduce the quantity of catalyst,or to bypass a catalyst bed for periodic maintenance or catalystremoval. Another mode of continuous operation utilizes a slurry of thecatalyst in an agitated pressure vessel, which is equipped with a filterleg to permit continuous removal of a solution of product in unreactedcyclobutanedione and/or a solvent. In this manner, a liquid reactant orreactant solution can be continuously fed to, and product solutioncontinuously removed from, an agitated pressure vessel containing anagitated slurry of the catalyst.

In one embodiment, the present invention provides processes forproducing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol of Formula II,comprising contacting a 2,2,4,4-tetraalkylcyclobutane-1,3-dione withhydrogen in the presence of an iridium-promoted cobalt-based catalystunder conditions of temperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol, wherein the alkyl radicals R₁,R₂, R₃ and R₄ each independently have 1 to 8 carbon atoms.

In one embodiment, the source of the promoter metal is Ir(OAc)_(x). Inone embodiment x=3. In other embodiments x=1 or 4. In other embodimentsx is determined by the relative proportion of the different iridiumacetate salts present, where iridium has more than one oxidation state.

In one embodiment, the iridium-promoted cobalt-based catalyst comprises0.01 to 10 weight percent (wt %) iridium, based on the total weight ofthe iridium-promoted cobalt-based catalyst. In one embodiment, theiridium-promoted cobalt-based catalyst comprises 0.5 to 7 wt % iridium.In one embodiment, the iridium-promoted cobalt-based catalyst comprises1 to 5 wt % iridium.

In one embodiment, the present invention provides processes forproducing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol of Formula II,comprising contacting a 2,2,4,4-tetraalkylcyclobutane-1,3-dione withhydrogen in the presence of an iridium-promoted cobalt-based catalystunder conditions of temperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol. In one embodiment, the alkylradical radicals R₁, R₂, R₃ and R₄ each independently have 1 to 4 carbonatoms. In one embodiment, the alkyl radical radicals R₁, R₂, R₃ and R₄each are methyl groups. In one embodiment, the2,2,4,4-tetraalkylcyclobutane-1,3-diol is2,2,4,4-tetramethylcyclobutane-1,3-diol. In one embodiment, the2,2,4,4-tetraalkylcyclobutane-1,3-dione is2,2,4,4-tetramethylcyclobutane-1,3-dione.

In one embodiment, the present invention provides processes forproducing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol of Formula II,comprising contacting a 2,2,4,4-tetraalkylcyclobutane-1,3-dione withhydrogen in the presence of an iridium-promoted cobalt-based catalystunder conditions of temperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol, wherein the alkyl radicals R₁,R₂, R₃ and R₄ each independently have 1 to 8 carbon atoms and whereinthe process further comprises a non-protic solvent. In one embodiment,the non-protic solvent comprises an unsaturated hydrocarbon, anon-cyclic ester, or ether. The term “non-cyclic ester” means the esteris not a lactone, although the alkanol or aliphatic carboxylic acidresidues of the ester may have cyclic rings. In one embodiment, thenon-cyclic ester contains 4 to 20 carbon atoms and comprises at leastone residue of an aliphatic carboxylic acid and at least one residue ofan alkanol. In one embodiment, the non-cyclic ester is selected fromisopropyl isobutyrate, isobutyl propionate, octyl acetate, isobutylisobutyrate, isobutyl acetate, and mixtures thereof.

In one embodiment, the present invention provides processes forproducing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol of Formula II,comprising contacting a 2,2,4,4-tetraalkylcyclobutane-1,3-dione withhydrogen in the presence of an iridium-promoted cobalt-based catalystunder conditions of temperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol, wherein the alkyl radicals R₁,R₂, R₃ and R₄ each independently have 1 to 8 carbon atoms and whereinthe process further comprises a protic solvent. In one embodiment, theprotic solvent comprises one or more solvents chosen from a monohydricalcohol, a dihydric alcohol, a polyhydric alcohol, and mixtures thereof.In one embodiment, the protic solvent comprises one or more solventschosen from a monohydric alcohol, a dihydric alcohol, or mixturesthereof. In one embodiment, the protic solvent comprises methanol orethylene glycol.

In one embodiment, the present invention provides processes forproducing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol of Formula II,comprising contacting a 2,2,4,4-tetraalkylcyclobutane-1,3-dione withhydrogen in the presence of an iridium-promoted cobalt-based catalystunder conditions of temperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol, wherein the alkyl radicals R₁,R₂, R₃ and R₄ each independently have 1 to 8 carbon atoms and whereinthe promoted cobalt-based catalyst comprises a support. In oneembodiment, the support comprises one or more of silica, alumina,aluminosilicate, silica/alumina, kieselguhr, titania, graphite, siliconcarbide, carbon, zirconia, chromate, barium chromate, zinc oxide, clay,and alumina-clay. In one embodiment, the support comprises a formselected from powder, extrudate, spheres, and pellets.

In one embodiment, the present invention provides processes forproducing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol of Formula II,comprising contacting a 2,2,4,4-tetraalkylcyclobutane-1,3-dione withhydrogen in the presence of an iridium-promoted cobalt-based catalystunder conditions of temperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol, wherein the alkyl radicals R₁,R₂, R₃ and R₄ each independently have 1 to 8 carbon atoms and whereinthe pressure ranges from 689 kPa (100 psi) to 41,368 kPa (6000 psi). Inone embodiment, the pressure ranges from 1380 kPa (200 psi) to 20,684kPa (3000 psi). In one embodiment, the pressure ranges from 2068 kPa(300 psi) to 14,789 kPa (2000 psi). In one embodiment, the temperatureranges from 75° C. to 250° C. In one embodiment, the temperature rangesfrom 120° C. to 200° C. In one embodiment, the temperature ranges from130° C. to 180° C.

In one embodiment, the present invention provides processes forproducing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol of Formula II,comprising contacting a 2,2,4,4-tetraalkylcyclobutane-1,3-dione withhydrogen in the presence of an iridium-promoted cobalt-based catalystunder conditions of temperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol, wherein the alkyl radicals R₁,R₂, R₃ and R₄ each independently have 1 to 8 carbon atoms and whereinthe 2,2,4,4-tetraalkylcyclobutane-1,3-diol comprisescis-2,2,4,4-tetramethylcyclobutane-1,3-diol andtrans-2,2,4,4-tetramethylcyclobutane-1,3-diol and the2,2,4,4-tetramethylcyclobutane-1,3-diol has a cis/trans molar ratio of0.3 to 0.9. In one embodiment, the2,2,4,4-tetramethylcyclobutane-1,3-diol has a cis/trans molar ratio of0.4 to 0.8. In one embodiment, the2,2,4,4-tetramethylcyclobutane-1,3-diol has a cis/trans molar ratioranging from 0.4 to 0.7.

In one embodiment, the present invention provides processes forproducing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol of Formula II,comprising contacting a 2,2,4,4-tetraalkylcyclobutane-1,3-dione withhydrogen in the presence of an iridium-promoted cobalt-based catalystunder conditions of temperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol, wherein the alkyl radicals R₁,R₂, R₃ and R₄ each independently have 1 to 8 carbon atoms and whereinthe 2,2,4,4-tetramethylcyclobutane-1,3-dione, the2,2,4,4-tetramethylcyclobutane-1,3-diol, or both are in the moltenphase, i.e., in a liquid phase without a solvent.

In one embodiment, the present invention provides processes forproducing 2,2,4,4-tetramethylcyclobutane-1,3-diol, comprising contacting2,2,4,4-tetramethylcyclobutane-1,3-dione, an iridium-promotedcobalt-based catalyst, a non-protic solvent, and hydrogen in ahydrogenation zone under conditions of temperature and pressuresufficient to form 2,2,4,4-tetramethylcyclobutane-1,3-diol. In one suchembodiment, the 2,2,4,4-tetramethylcyclobutane-1,3-dione and hydrogenare continuously fed into the hydrogenation zone. In one suchembodiment, the hydrogenation zone has a temperature ranging from 75° C.to 250° C. In one such embodiment, the pressure ranges from 689 kPa (100psi) to 41,368 kPa (6000 psi).

In one embodiment, the present invention provides processes forproducing 2,2,4,4-tetramethylcyclobutane-1,3-diol, comprising contacting2,2,4,4-tetramethylcyclobutane-1,3-dione, an iridium-promotedcobalt-based catalyst, a non-protic solvent, and hydrogen in ahydrogenation zone under conditions of temperature and pressuresufficient to form 2,2,4,4-tetramethylcyclobutane-1,3-diol, and furthercomprising continuously recovering an effluent comprising the2,2,4,4-tetramethylcyclobutane-1,3-diol and the solvent from thehydrogenation zone. In one such embodiment, the process furthercomprises continuously recycling a portion of the effluent to thehydrogenation zone. In one such embodiment, the process furthercomprises continuously recovering the effluent from the hydrogenationzone and recovering at least a portion of the2,2,4,4-tetramethylcyclobutane-1,3-diol from the effluent to form adepleted 2,2,4,4-tetramethylcyclobutane-1,3-diol stream. In one suchembodiment, at least a portion of the depleted2,2,4,4-tetramethylcyclobutane-1,3-diol stream is recycled to thehydrogenation zone. The term “depleted2,2,4,4-tetramethylcyclobutane-1,3-diol stream” means that the depletedstream has less 2,2,4,4-tetramethylcyclobutane-1,3-diol in it than theeffluent from which the depleted stream is derived. In one suchembodiment, the hydrogenation zone comprises a tubular, fixed bed, ortrickle bed reactor. In one such embodiment, the hydrogenation zonecomprises a stirred tank, a continuous stirred tank, or a slurryreactor. In one such embodiment, the2,2,4,4-tetramethylcyclobutane-1,3-diol has a cis/trans molar ratio of0.9 or less. In one such embodiment, the2,2,4,4-tetramethylcyclobutane-1,3-diol has a cis/trans molar ratio of0.3 or more.

In one embodiment, the present invention provides processes forproducing 2,2,4,4-tetramethylcyclobutane-1,3-diol comprising (1) feedingisobutyric anhydride to a pyrolysis zone, wherein the isobutyricanhydride is heated at a temperature of 350° C. to 600° C. to produce avapor effluent comprising dimethylketene, isobutyric acid, and unreactedisobutyric anhydride; (2) cooling the vapor effluent to condenseisobutyric acid and isobutyric anhydride and separating the condensatefrom the dimethylketene vapor; (3) feeding the dimethylketene vapor toan absorption zone, wherein the dimethylketene vapor is contacted withand dissolved in a solvent comprising an ester containing 4 to 20 carbonatoms and consisting of residues of an aliphatic carboxylic acid and analkanol to produce an absorption zone effluent comprising a solution ofdimethylketene in the solvent; (4) feeding the absorption zone effluentto a dimerization zone wherein the absorption zone effluent is heated ata temperature ranging from 70° C. to 140° C. to convert dimethylketeneto 2,2,4,4-tetramethylcyclobutane-1,3-dione to produce a dimerizationzone effluent comprising a solution of2,2,4,4-tetramethylcyclobutane-1,3-dione in the solvent; and (5)contacting the 2,2,4,4-tetramethylcyclobutane-1,3-dione with hydrogen inthe presence of an iridium-promoted cobalt-based catalyst underconditions of temperature and pressure sufficient to form a2,2,4,4-tetramethylcyclobutane-1,3-diol.

In one embodiment, the present invention provides processes forproducing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol of Formula II,comprising contacting a 2,2,4,4-tetraalkylcyclobutane-1,3-dione withhydrogen in the presence of an iridium-promoted cobalt-based catalyst,the catalyst comprising an alumina support, under conditions oftemperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol, wherein the alkyl radicals R₁,R₂, R₃ and R₄ each have 1 carbon atom, wherein the temperature rangesfrom 150° C. to 180° C., or 160° C. to 170° C., wherein the pressureranges from 34.5 to 100 barg, wherein the conversion is at least 95% andwherein the cis/trans molar ratio is greater than 0.60, or greater than0.63, or ranges from 0.63 to 0.69.

In one embodiment, the present invention provides processes forproducing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol of Formula II,comprising contacting a 2,2,4,4-tetraalkylcyclobutane-1,3-dione withhydrogen in the presence of an iridium-promoted cobalt-based catalyst,the catalyst comprising an alumina support, under conditions oftemperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol, wherein the alkyl radicals R₁,R₂, R₃ and R₄ each have 1 carbon atom, wherein the temperature rangesfrom 150° C. to 180° C., or 160° C. to 170° C., wherein the pressureranges from 34.5 to 100 barg, wherein the yield is at least 80% andwherein the cis/trans molar ratio is greater than 0.60, or greater than0.63, or ranges from 0.63 to 0.69.

In one embodiment, the present invention provides processes forproducing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol of Formula II,comprising contacting a 2,2,4,4-tetraalkylcyclobutane-1,3-dione withhydrogen in the presence of an iridium-promoted cobalt-based catalyst,the catalyst comprising an alumina support, under conditions oftemperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol, wherein the alkyl radicals R₁,R₂, R₃ and R₄ each have 1 carbon atom, wherein the temperature rangesfrom 120° C. to 150° C., or 130° C. to 140° C., wherein the pressureranges from 90 to 110 barg or 95 to 105 barg, wherein the selectivity isat least 85% or at least about 88%, wherein the yield is at least about80% or at least about 85% and wherein the cis/trans molar ratio rangesfrom greater than 0.50 to less than 0.60.

In one embodiment, the present invention provides processes forproducing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol of Formula II,comprising contacting a 2,2,4,4-tetraalkylcyclobutane-1,3-dione withhydrogen in the presence of an iridium-promoted cobalt-based catalyst,the catalyst comprising an alumina support, under conditions oftemperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol, wherein the alkyl radicals R₁,R₂, R₃ and R₄ each have 1 carbon atom, wherein the temperature rangesfrom 120° C. to 150° C., or 130° C. to 140° C., wherein the pressureranges from 34.5 to 100 barg, and wherein the cis/trans molar ratio isgreater than 0.5, or ranges from 0.51 to 0.53, or ranges from 0.51 toless than 0.60.

In one embodiment, the present invention provides processes for making2,2,4,4-tetramethylcyclobutane-1,3-diol comprising continuously feeding2,2,4,4-tetramethylcyclobutane-1,3-dione, a non-protic solvent, andhydrogen to a hydrogenation zone comprising an iridium-promotedcobalt-based catalyst at pressure of 689 kPa (100 psi) (7 bar) to 41,368kPa (6000 psi) (420 bar) and a hydrogenation temperature of 75° C. to250° C. and continuously recovering from said hydrogenation zone aneffluent comprising 2,2,4,4-tetramethylcyclobutane-1,3-diol and thenon-protic solvent. In another embodiment, the process may furthercomprise continuously recycling a portion of the effluent to thehydrogenation zone. The hydrogenation zone may be any suitable reactortype including, but not limited to, stirred tank, continuous stirredtank, slurry, tubular, fixed bed, and trickle bed. For example, theprocesses of the invention may be carried out in a trickle bed reactoroperated in the liquid phase. Certain embodiments of the invention arefurther described and illustrated by the following examples.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the scope or spirit of the invention. Otherembodiments of the invention will be apparent to those skilled in theart from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

Further embodiments of the invention include:

A process for producing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol ofFormula II, comprising contacting a2,2,4,4-tetraalkylcyclobutane-1,3-dione with hydrogen in the presence ofan iridium-promoted cobalt-based catalyst under conditions oftemperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol,

wherein each of the alkyl radicals R₁, R₂, R₃ and R₄ has independentlyfrom 1 to 8 carbon atoms.

The process according paragraph 71, further comprising contacting acobalt-based catalyst with a promoter to form the iridium-promotedcobalt-based catalyst.

The process according to any of the preceding embodiments in paragraphs71-72, further comprising contacting the cobalt-based catalyst with apromoter in solution to form the iridium-promoted cobalt-based catalyst,wherein the solution of promoter is prepared by dissolving Ir(OAc)_(x)in a suitable solvent.

The process according to any of the preceding embodiments in paragraphs71-73, wherein the iridium-promoted cobalt-based catalyst comprises 0.01to 10 weight percent (wt %) promoter metal, based on the total weight ofthe iridium-promoted cobalt-based catalyst.

The process according to any of the preceding embodiments in paragraphs71-74, wherein the iridium-promoted cobalt-based catalyst comprises 0.5to 7 wt % promoter, based on the total weight of the iridium-promotedcobalt-based catalyst.

The process according to any of the preceding embodiments in paragraphs71-75, wherein the iridium-promoted cobalt-based catalyst comprises 1 to5 wt % promoter, based on the total weight of the iridium-promotedcobalt-based catalyst.

The process according to any of the preceding embodiments in paragraphs71-76, wherein each of the alkyl radical radicals R₁, R₂, R₃, and R₄ hasindependently from 1 to 4 carbon atoms.

The process according to any of the preceding embodiments in paragraphs71-77, wherein each alkyl radical R₁, R₂, R₃, and R₄ is a methyl group.

The process according to any of the preceding embodiments in paragraphs71-78, wherein the 2,2,4,4-tetraalkylcyclobutane-1,3-dione is2,2,4,4-tetramethylcyclobutane-1,3-dione.

The process according to any of the preceding embodiments in paragraphs71-79, further comprising a non-protic solvent comprising an unsaturatedhydrocarbon, a non-cyclic ester, or an ether.

The process according to any of the preceding embodiments in paragraphs71-80, wherein the non-cyclic ester contains 4 to 20 carbon atoms andcomprises at least one residue of an aliphatic carboxylic acid and atleast one residue of an alkanol.

The process according to any of the preceding embodiments in paragraphs71-81, wherein the non-cyclic ester is chosen from isopropylisobutyrate, isobutyl propionate, octyl acetate, isobutyl isobutyrate,isobutyl acetate, and mixtures thereof.

The process according to any of the preceding embodiments in paragraphs71-82, wherein a protic solvent comprising one or more solvents chosenfrom a monohydric alcohol, a dihydric alcohol, a polyhydric alcohol, andmixtures thereof is present during the formation of the2,2,4,4-tetraalkylcyclobutane-1,3-diol.

The process according to any of the preceding embodiments in paragraphs71-83, wherein the protic solvent comprises methanol or ethylene glycol.

The process according to any of the preceding embodiments in paragraphs71-84, wherein the iridium-promoted cobalt-based catalyst comprises asupport, and wherein the support comprises one or more of silica,alumina, aluminosilicate, silica/alumina, kieselguhr, titania, graphite,silicon carbide, carbon, zirconia, chromate, barium chromate, zincoxide, clay, or alumina-clay.

The process according to any of the preceding embodiments in paragraphs71-85, wherein the support comprises a form chosen from powder,extrudate, spheres, or pellets.

The process according to any of the preceding embodiments in paragraphs71-86, wherein the pressure is from 100 psi to 6000 psi.

The process according to any of the preceding embodiments in paragraphs71-87, wherein the pressure is from 1380 kPa (200 psi) to 20,684 kPa(3000 psi).

The process according to any of the preceding embodiments in paragraphs71-88, wherein the pressure is from 300 psi to 2000 psi.

The process according to any of the preceding embodiments in paragraphs71-89, wherein the temperature is from 75° C. to 250° C.

The process according to any of the preceding embodiments in paragraphs71-90, wherein the temperature is from 120° C. to 200° C.

The process according to any of the preceding embodiments in paragraphs71-91, wherein the temperature is from 130° C. to 180° C.

The process according to any of the preceding embodiments in paragraphs71-92, wherein the 2,2,4,4-tetraalkylcyclobutane-1,3-diol comprisescis-2,2,4,4-tetramethylcyclobutane-1,3-diol andtrans-2,2,4,4-tetramethylcyclobutane-1,3-diol and the2,2,4,4-tetramethylcyclobutane-1,3-diol has a cis/trans molar ratio of0.3 to 0.8.

The process according to any of the preceding embodiments in paragraphs71-93, wherein the 2,2,4,4-tetramethylcyclobutane-1,3-diol has acis/trans molar ratio of 0.3 to 0.7.

The process according to any of the preceding embodiments in paragraphs71-94, wherein the 2,2,4,4-tetramethylcyclobutane-1,3-diol has acis/trans molar ratio of 0.4 to 0.7.

The process according to any of the preceding embodiments in paragraphs71-95, wherein the process is a continuous, semi-batch, or batchprocess.

The process according to any of the preceding embodiments in paragraphs71-96, wherein the 2,2,4,4-tetramethylcyclobutane-1,3-dione, the2,2,4,4-tetramethylcyclobutane-1,3-diol, or both are in the moltenphase.

A process for producing 2,2,4,4-tetramethylcyclobutane-1,3-diol,comprising contacting 2,2,4,4-tetramethylcyclobutane-1,3-dione, aniridium-promoted cobalt-based catalyst, a non-protic solvent, andhydrogen in a hydrogenation zone under conditions of temperature andpressure sufficient to form 2,2,4,4-tetramethylcyclobutane-1,3-diol.

The process according to the preceding embodiment in paragraph 98,wherein the 2,2,4,4-tetramethylcyclobutane-1,3-dione and hydrogen arecontinuously fed into the hydrogenation zone.

The process according to any of the preceding embodiments in paragraphs98-99, wherein the hydrogenation zone has a temperature from 75° C. to250° C.

The process according to any of the preceding embodiments in paragraphs98-100, wherein the pressure is from 100 psi to 6000 psi.

The process according to any of the preceding embodiments in paragraphs98-101, further comprising continuously recovering an effluentcomprising the 2,2,4,4-tetramethylcyclobutane-1,3-diol and the solventfrom the hydrogenation zone.

The process according to any of the preceding embodiments in paragraphs98-102, further comprising continuously recycling a portion of theeffluent to the hydrogenation zone.

The process according to any of the preceding embodiments in paragraphs98-103, further comprising continuously recovering the effluent from thehydrogenation zone and recovering at least a portion of the2,2,4,4-tetramethylcyclobutane-1,3-diol from the effluent to form adepleted 2,2,4,4-tetramethylcyclobutane-1,3-diol stream.

The process according to any of the preceding embodiments in paragraphs98-104, wherein at least a portion of the depleted2,2,4,4-tetramethylcyclobutane-1,3-diol stream is recycled to thehydrogenation zone.

The process according to any of the preceding embodiments in paragraphs98-105, wherein the hydrogenation zone comprises a tubular reactor, afixed bed reactor, trickle bed reactor, stirred tank reactor, continuousstirred tank reactor, or slurry reactor.

The process according to any of the preceding embodiments in paragraphs98-106, wherein the 2,2,4,4-tetramethylcyclobutane-1,3-diol has acis/trans molar ratio of 0.8 or less.

The process according to any of the preceding embodiments in paragraphs98-107, wherein the 2,2,4,4-tetramethylcyclobutane-1,3-diol has acis/trans molar ratio of 0.3 or more.

The process according to any of the preceding embodiments in paragraphs98-108, wherein the 2,2,4,4-tetramethylcyclobutane-1,3-diol has acis/trans molar ratio of 0.3-0.8.

A process for producing 2,2,4,4-tetramethylcyclobutane-1,3-diolcomprising:

-   -   (a) feeding isobutyric anhydride to a pyrolysis zone, wherein        the isobutyric anhydride is heated at a temperature of 350° C.        to 600° C. to produce a vapor effluent comprising        dimethylketene, isobutyric acid, and unreacted isobutyric        anhydride;    -   (b) cooling the vapor effluent to condense isobutyric acid and        isobutyric anhydride and separating the condensate from the        dimethylketene vapor;    -   (c) feeding the dimethylketene vapor to an absorption zone,        wherein the dimethylketene vapor is contacted with a solvent        comprising an ester containing 4 to 20 carbon atoms to produce        an absorption zone effluent comprising a solution of        dimethylketene in the solvent; wherein the ester comprises        residues of an aliphatic carboxylic acid and an alkanol;    -   (d) feeding the absorption zone effluent to a dimerization zone        wherein the absorption zone effluent is heated at a temperature        of from 70° C. to 140° C. to convert dimethylketene to        2,2,4,4-tetramethylcyclobutane-1,3-dione to produce an        dimerization zone effluent comprising a solution of        2,2,4,4-tetramethylcyclobutane-1,3-dione in the solvent; and    -   (e) contacting the 2,2,4,4-tetramethylcyclobutane-1,3-dione with        hydrogen in the presence of an iridium-promoted cobalt-based        catalyst under conditions of temperature and pressure sufficient        to form a 2,2,4,4-tetramethylcyclobutane-1,3-diol.

EXAMPLES

The following examples illustrate in general the processes of thepresent invention for the production of2,2,4,4-tetraalkylcyclobutane-1,3-diols by hydrogenation of2,2,4,4-tetraalkylcyclobutane-1,3-dione.

General

The following is a general description of the reactor system, catalystpreparation, hydrogenation process, and analytical methods usedhenceforward in Examples 1-6 unless otherwise specified.

The experiments were performed in a nanoflow parallel fixed bed reactorsystem under continuous trickle phase conditions in co-currentdownstream mode utilizing a tubular reactor that has an internaldiameter of 2 mm. The reactor is made by Advantium Technologies B.V. Thereactor was loaded with solid catalyst to fill a volume of 150 μl. Thecatalyst was reduced with hydrogen in-situ prior to testing. Thecatalyst reduction was carried out in the presence of isobutylisobutyrate at 100 barg (10,000 kPa or 1450 psig). Temperature wasincreased at a rate of 0.5° C./min from ambient temperature to 180° C.and held for 2 hours. All pressures are gauge pressure unless otherwisespecified as absolute pressure.

The 2,2,4,4-tetramethylcyclobutane-1,3-dione used in the experiments wasdiluted with isobutyl isobutyrate to a concentration of 10 wt % andheated to 85° C. The 2,2,4,4-tetramethylcyclobutane-1,3-dione/isobutylisobutyrate feed mixture was fed at the top of the reactor vessel alongwith hydrogen and contacted with the catalyst. After the system reachedthe correct process conditions, the system was held at these conditionsfor 2 hours, which was considered to be the reaction time. The reactoreffluent stream containing crude 2,2,4,4-tetramethylcyclobutane-1,3-diolproduct was removed from the bottom of the reactor.

The reactor effluent stream was sampled using a Gilson 233 liquidsampler. 30 μl of the reaction sample was diluted with 970 μlisopropanol and analyzed by capillary gas-liquid chromatography (“GC”)using a TraceGC from Thermo Finnigan with a CombiPal autosampler fromCTC Analytics, with a FID detector. The GC samples were injected onto a0.25 micron (30 m×0.32 mm) Varian CP Wax 52 CB column. For eachanalysis, the initial temperature of the column was set at 80° C., heldfor 2 minutes, ramped to 90° C. at a rate of 5° C./min, ramped to 240°C. at a rate of 20° C./min, and then held for 3.5 min at 240° C. Resultsare given as GC area percentages, normalized for isobutyl isobutyrate.

The following abbreviations apply throughout the working examples andtables:

TMCB 2,2,4,4-tetramethylcyclobutane-1,3-dione Ring-open Ketol1-hydroxy-2,2,4-trimethyl-3-pentanone (a product of the partialhydrogenation and ring opening of2,2,4,4-tetramethylcyclobutane-1,3-dione) Cyclic Ketol3-hydroxy-2,2,4,4-tetramethylcyclobutanone (a product of the partialhydrogenation of 2,2,4,4- tetramethylcyclobutane-1,3-dione) TMPD2,2,4-trimethyl-1,3-pentanediol (a product of the hydrogenation ofRing-opened Ketol) Cis-Diol cis-2,2,4,4-tetramethylcyclobutane-1,3-diolTrans-Diol trans-2,2,4,4-tetramethylcyclobutane-1,3-diol

The conversion, selectivity, and yield of the hydrogenation process aswell as the cis:trans ratio of the2,2,4,4-tetramethylcyclobutane-1,3-diol product were calculated on thebasis of GC area percentages using the following formulas:

${{Conversion}\mspace{14mu}\%} = {\frac{\left( {{moles}\mspace{14mu}{TMCB}\mspace{14mu}{fed}} \right) - \left( {{moles}\mspace{14mu}{TMCB}\mspace{14mu}{remaining}} \right)}{\left( {{moles}\mspace{14mu}{TMCB}\mspace{14mu}{fed}} \right)} \times 100}$${{Yield}\mspace{14mu}\%} = {\frac{\left( {{{moles}\mspace{14mu}{Cis}} - {Diol}} \right) + \left( {{{moles}\mspace{14mu}{Trans}} - {Diol}} \right)}{\left( {{moles}\mspace{14mu}{TMCB}\mspace{14mu}{fed}} \right)} \times 100}$$\begin{matrix}{{Selectivity} = \frac{\left( {{{moles}\mspace{14mu}{Cis}} - {Diol}} \right) + \left( {{{moles}\mspace{14mu}{Trans}} - {Diol}} \right)}{\left( {{moles}\mspace{14mu}{TMCB}\mspace{14mu}{fed}} \right) - \left( {{moles}\mspace{14mu}{TMCB}\mspace{14mu}{remaining}} \right)}} \\{= \frac{Yield}{Conversion}}\end{matrix}$${{{Cis}/{Trans}}\mspace{14mu}{Ratio}} = \frac{\left( {{{moles}\mspace{14mu}{Cis}} - {Diol}} \right)}{\left( {{{moles}\mspace{14mu}{Trans}} - {Diol}} \right)}$

Comparative Example 1

Using the general procedure described above,2,2,4,4-tetramethylcyclobutane-1,3-dione was hydrogenated using anon-promoted supported cobalt catalyst at temperatures of 135° C. and165° C., reactor pressures of 34.5 barg (3450 kPa) and 100 barg (10,000kPa), and a liquid space velocity of 25 hr⁻¹. The catalyst used was anA280 cobalt on alumina catalyst obtained from Engelhard Corporation.

The results are shown in Table 1.

TABLE 1 Hydrogenation of 2,2,4,4-tetramethylcyclobutane-1,3-dione usingnon-promoted cobalt catalyst. Comparative Example 1a 1b 1c 1d Metal CoCo Co Co Promoter none none none none Support alumina alumina aluminaalumina Temperature 135 135 165 165 (° C.) Pressure (barg) 34.5 100 34.5100 TMCB % 22.9 10.4 0 0 Ring-Open 1.2 1.4 5.6 5.8 Ketol % Cyclic Ketol% 67.6 71.5 11.8 7.2 TMPD % 0 0 5.1 4.0 Cis-Diol % 2.5 5.1 27.0 28.8Trans-Diol % 5.9 11.7 50.5 54.2 Conversion % 76.8 89.5 100 100Selectivity % 8.3 16.6 77.4 82.9 Yield % 6.3 14.8 77.4 82.9 Cis/Trans0.42 0.44 0.54 0.53

Example 2

Using the general procedure described above,2,2,4,4-tetramethylcyclobutane-1,3-dione was hydrogenated using aniridium-promoted cobalt on alumina catalyst at temperatures of 135° C.and 165° C., reactor pressures of 34.5 barg (3450 kPa) and 100 barg(10,000 kPa), and a liquid space velocity of 25 hr⁻¹. Theiridium-promoted cobalt on alumina catalyst was prepared from a cobalton alumina catalyst obtained from Engelhard Corporation (A280) asfollows:

The cobalt on alumina catalyst was ground and sieved to obtain the0.2-0.4 mm sieve fraction. 500 mg of the cobalt on alumina catalyst werewetted with 500 μl of a 6.83 wt % solution of Ir(OAc)_(x) in water, andthen dried in air at 50° C. for 16 hr and at 110° C. for 4 hr. TheIr(OAc)_(x) was obtained from Heraeus. After drying, the catalyst wascalcined in air by heating from ambient temperature to 400° C., at arate of 2° C./min, and maintaining the catalyst at 400° C. for 2 hr. Theresults of the hydrogenation of TMCB using the iridium-promoted cobaltcatalyst thus prepared are shown in Table 2.

TABLE 2 Hydrogenation of 2,2,4,4-tetramethylcyclobutane-1,3-dione usingiridium-promoted cobalt catalyst. Example 2a 2b 2c 2d Metal Co Co Co CoPromoter Ir Ir Ir Ir Support alumina alumina alumina alumina Temperature135 135 165 165 (° C.) Pressure 34.5 100 34.5 100 (barg) TMCB % 2.2 0 04.9 Ring-Open 0.6 0 0.9 1.4 Ketol % Cyclic Ketol % 57.3 11.8 6.9 4.8TMPD % 0.3 0 5.0 4.1 Cis-Diol % 13.1 29.8 33.6 34.5 Trans-Diol % 24.857.9 53.2 50.3 Conversion % 97.7 100 100 95.0 Selectivity % 38.2 88.087.2 84.7 Yield % 37.3 88.0 87.2 80.5 Cis/Trans 0.53 0.51 0.63 0.69

1. A process for producing a 2,2,4,4-tetraalkylcyclobutane-1,3-diol ofFormula II, comprising contacting a2,2,4,4-tetraalkylcyclobutane-1,3-dione with hydrogen in the presence ofan iridium-promoted cobalt-based catalyst under conditions oftemperature and pressure sufficient to form a2,2,4,4-tetraalkylcyclobutane-1,3-diol,

wherein each of the alkyl radicals R₁, R₂, R₃ and R₄ has independentlyfrom 1 to 8 carbon atoms and wherein the iridium-promoted cobalt-basedcatalyst comprises an alumina support.
 2. The process according to claim1, further comprising contacting a cobalt-based catalyst with a promoterto form the iridium-promoted cobalt-based catalyst.
 3. The processaccording to claim 1, further comprising contacting a cobalt-basedcatalyst with a promoter in solution to form the iridium-promotedcobalt-based catalyst, wherein the solution of promoter is prepared bydissolving a Ir(OAc)_(x) in a suitable solvent.
 4. The process accordingto claim 1, wherein the iridium-promoted cobalt-based catalyst comprises0.01 to 10 weight percent (wt %) promoter metal, based on the totalweight of the iridium-promoted cobalt-based catalyst.
 5. The processaccording to claim 1, wherein each of the alkyl radical radicals R₁, R₂,R₃, and R₄ has, independently from each other, 1 to 4 carbon atoms. 6.The process according to claim 1, wherein each alkyl radical R₁, R₂, R₃,and R₄ is a methyl group.
 7. The process according to claim 1, wherein anon-protic solvent comprising an unsaturated hydrocarbon, a non-cyclicester, an ether or mixtures thereof is present.
 8. The process accordingto claim 7, wherein the non-cyclic ester is chosen from isopropylisobutyrate, isobutyl propionate, octyl acetate, isobutyl isobutyrate,isobutyl acetate, and mixtures thereof.
 9. The process according toclaim 1, wherein a protic solvent comprising one or more solvents chosenfrom monohydric alcohol, a dihydric alcohol, a polyhydric alcohol, andmixtures thereof is present.
 10. The process according to claim 9,wherein the protic solvent comprises methanol, ethylene glycol ormixtures thereof.
 11. The process according to claim 1, wherein thepressure is from 100 psi to 6000 psi.
 12. The process according to claim1, wherein the pressure is from 300 psi to 2000 psi.
 13. The processaccording to claim 1, wherein the temperature is from 75° C. to 250° C.14. The process according to claim 1, wherein the temperature is from130° C. to 180° C.
 15. The process according to claim 1, wherein the2,2,4,4-tetraalkylcyclobutane-1,3-diol comprisescis-2,2,4,4-tetramethylcyclobutane-1,3-diol andtrans-2,2,4,4-tetramethylcyclobutane-1,3-diol and the2,2,4,4-tetramethylcyclobutane-1,3-diol has a cis/trans molar ratio of0.3 to 0.8.
 16. The process according to claim 15, wherein the2,2,4,4-tetramethylcyclobutane-1,3-diol has a cis/trans molar ratio of0.4 to 0.7.
 17. A process for producing2,2,4,4-tetramethylcyclobutane-1,3-diol, comprising contacting2,2,4,4-tetramethylcyclobutane-1,3-dione, an iridium-promotedcobalt-based catalyst, a non-protic solvent, and hydrogen in ahydrogenation zone under conditions of temperature and pressuresufficient to form 2,2,4,4-tetramethylcyclobutane-1,3-diol.
 18. Theprocess according to claim 17, wherein the2,2,4,4-tetramethylcyclobutane-1,3-dione and hydrogen are continuouslyfed into the hydrogenation zone.
 19. The process according to claim 17,wherein the hydrogenation zone has a temperature from 75° C. to 250° C.20. The process according to claim 17, wherein the pressure is from 100psi to 6000 psi.
 21. The process according to claim 17, furthercomprising continuously recycling a portion of an effluent from thehydrogenation zone back into the hydrogenation zone.
 22. The processaccording to claim 17, wherein the hydrogenation zone comprises atubular reactor, a fixed bed reactor, a trickle bed reactor, a stirredtank reactor, a continuous stirred tank reactor, or a slurry reactor.23. The process according to claim 17, wherein the2,2,4,4-tetramethylcyclobutane-1,3-diol has a cis/trans molar ratio of0.3-0.8.
 24. A process for producing2,2,4,4-tetramethylcyclobutane-1,3-diol comprising: (a) feedingisobutyric anhydride to a pyrolysis zone, wherein the isobutyricanhydride is heated at a temperature of 350° C. to 600° C. to produce avapor effluent comprising dimethylketene, isobutyric acid, and unreactedisobutyric anhydride; (b) cooling the vapor effluent to condenseisobutyric acid and isobutyric anhydride and separating the condensatefrom the dimethylketene vapor; (c) feeding the dimethylketene vapor toan absorption zone, wherein the dimethylketene vapor is contacted with asolvent comprising an ester containing 4 to 20 carbon atoms to producean effluent comprising a solution of dimethylketene in the solvent;wherein the ester comprises residues of an aliphatic carboxylic acid andan alkanol; (d) feeding the absorption zone effluent to a dimerizationzone wherein the effluent is heated at a temperature of from 70° C. to140° C. to convert dimethylketene to2,2,4,4-tetramethylcyclobutane-1,3-dione to produce an effluentcomprising a solution of 2,2,4,4-tetramethylcyclobutane-1,3-dione in thesolvent; and (e) contacting the 2,2,4,4-tetramethylcyclobutane-1,3-dionewith hydrogen in the presence of an iridium-promoted cobalt-basedcatalyst comprising an alumina support under conditions of temperatureand pressure sufficient to form a2,2,4,4-tetramethylcyclobutane-1,3-diol.